Expression and functional analyses of Niemann–Pick C2 gene in Phytoseiulus persimilis Athias-Henriot

Abstract

Abstract As a new protein class of semiochemical binding and transporting, Niemann-Pick proteins type C2 (NPC2) in arthropods has received more attentions in recent decade. However, the gene function has not been studied in phytoseiid mites for biocontrol potential. In current study, we identified and cloned a new NPC2 gene PpNPC2a from transcriptome of a predatory mite Phytoseiulus persimilis Athias-Henriot. PpNPC2a encoded 181 amino acids with a conserved ML domain. From phylogenetic analyses, PpNPC2a was found homologous to NPC2-1 of Galendromus occidentalis Nesbitt. We also measured gene expression in different stages and tissues in P. persimilis. PpNPC2a transcript was significantly higher in female adults than in male adults or other immature stages. Due to tiny body size of predatory mites, we only examined tissue expressions in two sections, posterior part of which was found higher gene transcription of PpNPC2a. To investigate the potential function of PpNPC2a in P. persimilis, we interfered gene expression in female adults by feeding dsRNA. The relative expression was found decreased by 59.1% and 78.2% in 24 h and 72 h after treatments, respectively. The dsNPC2a-treated females had less preference to spider mite infested plant, but we did not find their insensitiveness in response to four representative compounds of HIPVs, including 4,8,12-trimethyl-1,3,7,11-tridecatetraene (TMTT), Methyl salicylate (MeSA), β-Caryophyllene and Linalool. These results indicated PpNPC2a may play a role in P. persimilis in response to plant volatiles.